Alkylphosphonodiamide herbicides

ABSTRACT

Herbicides have the formula ##STR1## in which R 1  is C 2  -C 8  alkyl or C 5  -C 8  cycloalkyl; 
     R 2  is hydrogen or C 1  -C 4  alkyl; 
     R 3  is phenyl, optionally substituted by C 1  -C 4  alkyl, C 1  -C 4  haloalkyl, C 1  -C 4  haloalkoxy, one or more halogens, one or two C 1  -C 4  alkoxy groups, one C 1  -C 4  alkyl and one C 1  -C 4  alkoxy groups, or if R 2  is C 1  -C 4  alkyl, R 3  may also be phenyl substituted by two C 1  -C 4  haloalkyl groups; pyridyl or tolylsulfonyl; 
     R 4  and R 5  are independently C 2  -C 6  alkyl.

FIELD OF THE INVENTION

This invention relates to certain novel alkylphosphonodiamide compounds which demonstrate herbicidal activity.

Some herbicidal alkyl phosphonodiamides are disclosed in British Patent 1,350,286 of Nissan Chemical Industries, Ltd. and in Bakumenko et al., Khim. Sel'sk. Khoz., vol. 4, p. 691 (1966).

DESCRIPTION OF THE INVENTION

According to this invention, compounds of the following type have been found to exhibit herbicidal activity: ##STR2## in which R₁ is C₂ -C₈ alkyl or C₅ -C₈ cycloalkyl;

R₂ is hydrogen or C₁ -C₄ alkyl;

R₃ is phenyl, optionally substituted by C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ haloalkoxy, one or more halogens, one or two C₁ -C₄ alkoxy groups, one C₁ -C₄ alkyl and one C₁ -C₄ alkoxy group, or if R₂ is C₁ -C₄ alkyl, R₃ may also be phenyl substituted by two C₁ -C₄ haloalkyl groups; pyridyl or tolylsulfonyl; and

R₄ and R₅ are independently C₂ -C₆ alkyl.

Two compounds within this genus were synthesized by Mel'nikov et al., Zh. Obshch. Khim., 38. 2648 (1968) in the course of research in organophosphorus chemistry. They correspond to formula (I) in which R₁ is isopropyl, R₂ is hydrogen, R₃ is phenyl or 3-chlorophenyl, and R₄ and R₅ are both ethyl.

Most compounds of this invention, however, are novel. The novel compounds correspond to formula (I) in which:

R₁ is C₂ -C₈ alkyl or C₅ -C₈ cycloalkyl;

R₂ is hydrogen or C₁ -C₄ alkyl;

R₃ is phenyl, optionally substituted by C₁ -C₄ alkyl, C₁ -C₄ haloalkyl, C₁ -C₄ haloalkoxy, NR₆ R₇, one or more halogens, one or two C₁ -C₄ alkoxy groups, one C₁ -C₄ alkyl and one C₁ -C₄ alkoxy group, or if R₂ is C₁ -C₄ alkyl, R₃ may also be phenyl substituted by two C₁ -C₄ haloalkyl groups; pyridyl or tolylsulfonyl and

R₄ and R₅ are independently C₃ -C₆ alkyl; provided that if R₂ is hydrogen and R₃ is phenyl or 3-chlorophenyl, then R₄ and R₅ are both C₃ -C₆ alkyl

The term "alkyl" includes straight and branched chained saturated acyclic hydrocarbyl moieties having the indicated number of carbon atoms. Preferred alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, t-butyl, i-butyl, and n-amyl. The term "cycloalkyl" includes saturated cyclical hydrocarbyl moieties, such as cyclopentyl and cyclohexyl. The term "halogen" includes chloro, bromo, fluoro and iodo. The terms "haloalkyl" and "haloalkoxy" include both mono- and polyhalogenated groups in which the halogens may be identical or different. Substituted phenyl groups may contain one or more of the indicated substituents, which may be the same or different. The substituted phenyl groups contain from 1 to 3, preferably from 1 to 2, substituents, which may be located at convenient points on the phenyl ring.

Preferred compounds are those in which:

R₁ is C₂ -C₆ (most preferably C₃ -C₆) alkyl or C₅ -C₆ cycloalkyl;

R₂ is C₁ -C₄ alkyl;

R₃ is phenyl, optionally substituted by methyl, trifluoromethyl, trifluoromethoxy, one or two methoxy groups, one methyl and one methoxy group, or one or two halogens (most preferably chloro); or pyridyl; and

R₄ and R₅ are independently C₃ -C₄ alkyl.

As used herein, the term "herbicide" means a compound or composition which adversely controls or modifies the growth of plants. By the term "herbicidally effective amount" is meant any amount of such compound or composition which causes an adverse modifying effect upon the growth of plants. By "plants", it is meant germinant seeds, emerging seedlings and established vegetation, including roots and above-ground portions. Such controlling or modifying effects include all deviations from natural development, such as killing, retardation, defoliation, desiccation, regulation, stunting, tillering, leaf burn, dwarfing, and the like.

The compounds of this invention have been found to be active herbicides, particularly post-emergent herbicides; i.e. they may be applied to control or kill existing vegetation which has already emerged from the soil. Some of the compounds of this invention have demonstrated such post-emergence herbicidal activity in a relatively short time, and against some weeds, with a very strong effect. Herbicides having such rapid and extensive post-emergence activity are sometimes referred to as "contact and burn" or "burn-down" herbicides and are used, among other applications, for clearing vegetation from land such as building lots, highway median strips, railroad track beds, and crop land prior to planting or in minimum till or no-till farming. Some of the compounds of this invention also demonstrate pre-emergence activity, that is, control or killing of vegetation by application prior to the emergence of vegetation from the soil. Pre-emergence herbicides may be applied by techniques such as incorporation into, or spraying or spreading onto, the surface of the soil.

Compounds showing "contact-and-burn" effect, but little or no pre-emergence activity, may be useful in clearing land prior to planting since planting of a crop can be done relatively soon after the herbicide is applied.

According to one process, the compounds of this invention may be prepared from starting phosphonodichlorides and appropriate amines, in one or two steps, by the general reaction ##STR3## Preferably the two amines are reacted stepwise with the alkylphosphonyl dichloride.

Processes of this type are generally carried out at temperatures of from about 0° to about 200° C., preferably from about 25° to about 110° C. An inert solvent, such as toluene or methylene chloride, is usually employed. In addition, a tertiary amine such as triethylamine or dimethylaniline, optionally in combination with lithium diisopropylamide, may be used.

Alternatively, compounds in which R₂ is C₁ -C₄ alkyl may be prepared from corresponding compounds in which R₂ is hydrogen, by alkylation: ##STR4## (X being chloro, bromo or iodo).

The following represent examples of preparation of compounds of this invention:

EXAMPLE 1 Preparation of N-methyl, N-phenyl, N',N'-di-(n-propyl)-propylphosphonodiamide (Compound No. 2 herein)

In a flask was placed 25 g (155.3 mmol) n-propylphosphonodichloride dissolved in methylene chloride. The mixture was held at 0° C., and 21.9 ml (156.8 mmol) triethylamine was added dropwise. The mixture was stirred for 15 minutes, then 21.5 ml (156.8 mmol) di(n-propyl)amine was added dropwise and the reaction mixture was stirred a further two hours. It was then quenched with 50 ml water, diluted with 100 ml hexane, vacuum filtered, dried and condensed, producing 32.7 g of an oil, which was determined by spectroscopic analysis to be N,N-di(n-propyl)propylphosphonochloride (94% purity).

The monochloride product obtained above (2.5 g, 11.9 mmol) was dissolved in toluene and maintained at 0° C. Then, 1.4 ml (12.7 mmol) N-methylaniline was added dropwise. Ten minutes later, 8.0 ml (12.2 mmol) lithium diisopropylamide was added. The reaction was stirred overnight, quenched with water, and extracted with 100 ml of diethyl ether. The aqueous layer was removed. The organic layer was washed with concentrated aqueous sodium bicarbonate and the aqueous layer again removed. The organic layer was then dried, and solvent was stripped off to produce 1.9 g of an oil, identified as the desired product by spectroscopic analyses. The purity of the oil was determined to be 94%.

EXAMPLE 2

Preparation of N-methyl, N-(4-ethylphenyl), N',N'-di-n-propyl propylphosphonodiamide (Compound No. 12 herein)

This example illustrates the production of a compound in which R₂ is phenyl from a corresponding compound in which R₂ is hydrogen.

In a flask there was placed 1.9 g (6.1 mmol) N-(4-ethylphenyl), N',N'-di(n-propyl)propylphosphonodiamide in 10 ml dry tetrahydrofuran. In a second flask were placed 0.30 g (6.2 mmol) sodium hydride in 20 ml dry hexane. The contents of the second flask were mixed to remove an oil dispersion. The hexane was then removed and 15 ml dry tetrahydrofuran was added. The tetrahydrofuran solution of the phosphonodiamidate was then added dropwise to the flask containing the sodium hydride and the solution was then mixed for 30 minutes. Then, a solution of 1.2 ml (I8.4 mmol) methyl iodide in about 3 ml tetrahydrofuran was added, dropwise. After stirring for 2 hours, the reaction mixture was quenched with water, diluted with diethyl ether, washed with 10% hydrochloric acid and then with sodium bicarbonate solution, dried and condensed. There was obtained 1.0 g of an oil (93% purity), identified by spectroscopic analyses as the desired compound.

Table I depicts representative compounds of this invention, prepared by one of the processes described above.

Most compounds were obtained as oils. The structures of all compounds were determined by spectroscopic analyses.

                  TABLE I                                                          ______________________________________                                          ##STR5##                                                                      Cmpd.                                                                          No.   R.sub.1 R.sub.2 R.sub.3      R.sub.4                                                                              R.sub.5                               ______________________________________                                          1.   n-C.sub.4 H.sub.9                                                                      CH.sub.3                                                                               C.sub.6 H.sub.5                                                                             n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                      2.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               C.sub.6 H.sub.5                                                                             n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                      3.   n-C.sub.3 H.sub.7                                                                      C.sub.2 H.sub.5                                                                        C.sub.6 H.sub.5                                                                             n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                      4.   n-C.sub.3 H.sub.7                                                                      n-C.sub.4 H.sub.9                                                                      C.sub.6 H.sub.5                                                                             n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                      5.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               4-ClC.sub.6 H.sub.4                                                                         n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                      6.   n-C.sub.4 H.sub.9                                                                      CH.sub.3                                                                               4-ClC.sub.6 H.sub.4                                                                         n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                      7.   n-C.sub.4 H.sub.9                                                                      H       4-CH.sub.3 OC.sub.6 H.sub.4                                                                 n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                      8.   n-C.sub.3 H.sub.7                                                                      i-C.sub.3 H.sub.7                                                                      C.sub.6 H.sub.5                                                                             n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                      9.   n-C.sub.4 H.sub.9                                                                      i-C.sub.3 H.sub.7                                                                      C.sub.6 H.sub.5                                                                             n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     10.   n-C.sub.3 H.sub.7                                                                      H       4-C.sub.2 H.sub.5 C.sub.6 H.sub.4                                                           n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     11.   C.sub.2 H.sub.5                                                                        CH.sub.3                                                                               C.sub.6 H.sub.5                                                                             n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     12.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               4-C.sub.2 H.sub.5 C.sub.6 H.sub.4                                                           n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     13.   n-C.sub.4 H.sub.9                                                                      n-C.sub.4 H.sub.9                                                                      C.sub.6 H.sub.5                                                                             n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     14.   n-C.sub.3 H.sub.7                                                                      H       3-CF.sub.3 C.sub.6 H.sub.4                                                                  n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     15.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               2-CH.sub.3 C.sub.6 H.sub.4                                                                  n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     16.   n-C.sub.3 H.sub.7                                                                      H       3-CH.sub.3 C.sub.6 H.sub.4                                                                  n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub. 7                    17.   n-C.sub.3 H.sub.7                                                                      H       2,4-OCH.sub.3 C.sub.6 H.sub.3                                                               n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     18.   n-C.sub.3 H.sub.7                                                                      H       C.sub.6 H.sub.5                                                                             n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     19.   n-C.sub.3 H.sub.7                                                                      H       2-CH.sub.3,4-OCH.sub.3 C.sub.6 H.sub.3                                                      n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     20.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               3-CF.sub.3 C.sub.6 H.sub.4                                                                  n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     21.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               3,5-CF.sub.3 C.sub.6 H.sub.3                                                                n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     22.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               2-pyridyl    n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     23.   n-C.sub.3 H.sub.7                                                                      H       2-CH.sub.3 C.sub.6 H.sub.4                                                                  n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     24.   n-C.sub.3 H.sub.7                                                                      H       4-CH.sub.3 C.sub.6 H.sub.4                                                                  n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     25.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               2-CH.sub.3,4-OCH.sub.3 C.sub.6 H.sub.4                                                      n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     26.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               3-CH.sub.3 C.sub.6 H.sub.4                                                                  n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     27.   n-C.sub.3 H.sub.7                                                                      H       3,4-ClC.sub.6 H.sub.3                                                                       n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     28.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               3,4-ClC.sub.6 H.sub.3                                                                       n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     29.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               4-CH.sub.3 C.sub.6 H.sub.3 SO.sub.2                                                         n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     30.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               2,4-OCH.sub.3 C.sub.6 H.sub.3                                                               n-C.sub.3 H.sub.7                                                                    n-C.sub.3 H.sub.7                     31.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               C.sub.6 H.sub.5                                                                             n-C.sub.4 H.sub.9                                                                    n-C.sub.4 H.sub.9                     32.   n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                               C.sub.6 H.sub.5                                                                             C.sub.2 H.sub.5                                                                      C.sub.2 H.sub.5                       ______________________________________                                    

Herbicidal Activity Tests

Compounds in Table I were tested for herbicidal activity as follows:

The herbicidal effect was observed by comparing the extent of weed control in test flats treated with the compounds against that occurring in similar non-treated control flats. All were applied at 3.57 lb/A (4 kg/ha) to pre-emergence and post-emergence screening flats. An 80 gal/A (748.3 1/ha) spray volume was utilized. Post-emergence flats were seeded 12 days prior to treatment. Pre-emergence flats were seeded one day prior to treatment. Overhead watering of pre-emergence flats and soil surface watering of post-emergence flats, so as to avoid wetting the foliage, were carried out for the duration of the test.

Weed seeds were planted in a flat at a seed depth of 0.5 inch (1.3 cm). Soil for flats was prepared using loam soil fortified with 17--17--17 fertilizer (N--P₂ O₅ --K₂ O on a weight basis) and Captan 80W fungicide. The test weeds were as follows:

    ______________________________________                                         COMMON NAME        SCIENTIFIC NAME                                             ______________________________________                                         green foxtail      Setaria viridis                                             watergrass         Echinochloa crusgalli                                       wild oat           Avena fatua                                                 annual morning glory                                                                              Ipomoea purpurea                                            velvetleaf         Abutilon theophrasti                                        wild mustard       Brassica kaber                                              yellow nutsedge    Cyperus esculentus                                          ______________________________________                                    

The spray solutions were prepared by dissolving 240 mg of test compound in 20 ml of acetone containing 1% polyoxyethylene sorbitan monolaurate emulsifier, then adding 20 ml of water to the resulting solution. The stock solutions were applied using a linear spray table. Pre-emergence flats are raised to the level of the post-emergence foliage canopy by setting the flats on a wooden block.

The degree of weed control was visually assessed and recorded as percentage control compared to the growth of the same species in an untreated check flat of the same age. The rating scale ranges from 0 to 100%, where 0 equals no effect with plant growth equal to the untreated control, and 100 equals complete kill.

Ratings were taken in pre-emergence tests approximately 15-18 days after treatment (DAT). In post-emergence tests, ratings were taken at two intervals. On the sixth day after treatment, overall control was rated, as an indication of total vegetative control, or "contact and burn" activity. Approximately 18 days after treatment, the tests were rated for overall post-emergence activity.

Results are listed in Table II below, expressed as average control of the three grassy (GR) (wild oat, watergrass, foxtail) and three broadleaf weeds (BL) (morning glory, mustard, velvetleaf), and of nutsedge (NS).

                                      TABLE II                                     __________________________________________________________________________            % Control, 4 kg/ha                                                             Pre-emergence   Post-emergence                                          Compound                                                                              18 DAT          6 DAT           15-18 DAT                               No.    GR avg.                                                                              BL avg.                                                                              NS  GR avg.                                                                              BL avg.                                                                              NS  GR avg.                                                                              BL avg.                                                                              NS                          __________________________________________________________________________      1.    0      0    0   50    100   0   90    100   0                            2.    0     40    0   80    100   0   60    100   0                            3.    0     33    0   80    90    0   83    97    0                            4.    10    33    0   80    100   0   93    100   0                            5.    0     60    0   50    90    0   70    97    0                            6.    0      0    0   80    100   0   80    100   0                            7.    0      0    0   30    90    0   38    95    0                            8.    28    27    0   80    100   10  90    100   20                           9.    0      0    0   --    --    --  43    100   0                            10.*  0      0    0   --    --    --    3   83    0                           11.    0     33    0   80    90    0   87    87    0                           12.    0      0    0   80    100   5   87    100   0                           13.    0     33    0   50    100   0   57    100   0                           14.    0      0    0   10    20    0    3    67    0                           15.    0     20    0   95    100   25  97    100   10                          16.    0      3    0   60    90    10  53    90    0                           17.    0      0    0   50    95    10  43    93    0                           18.    0     28    0   20    20    0    0     0    0                           19.    0     20    0   60    95    0   50    92    0                            20.** 0      0    0   85    85    20  77    92    0                           21.    0      0    0   40    85    0   17    93    0                           22.    --    --    --  70    95    0   --    --    --                          23.    66    66    0   80    80    10   6    55    10                          24.    0     100   0   20    90    0    3    86    0                           25.    0     50    0   85    98    50  53    100   10                          26.    0     53    0   85    100   50  65    100   10                          27.    0     25    0   30    85    0   13    58    0                           28.    33    20    0   30    100   10   0    100   5                           29.    0      0    0   20    90    5    1    91    0                           30.    0      0    0   40    100   10  31    100   0                           31.    0     36    0   80    90    20  63    100   0                           32.    3      6    0   30    90    5   13    96    0                           __________________________________________________________________________      *Application rate  1.5 kg/ha                                                   **Application rate  2.8 kg/ha                                            

Selected compounds were further tested against the same weeds at a lower application rate of 1.5 kg/ha. In general, control of grassy weeds was lower, but for the most part, control of broadleaf weeds remained at 80% or above.

In practice, a pure compound can be used as a herbicide. However, in general, the compounds are first formulated with one or more inert carriers or diluents suitable for herbicidal use, before being applied.

The compositions or formulations, including a compound as described herein, may exist in any one of a number of solid or liquid forms. Examples of liquid forms are emulsifiable concentrates, flowables and pastes. Such compositions may contain, in addition to the active compound or compounds, various carriers or diluents; surface active agents (wetting agents, dispersing agents and/or emulsifying agents); solvents (water, or organic solvents such as aromatic solvents or chlorinated aliphatic solvents); adhesives; thickeners; binders; antifoaming agents; and other substances as mentioned herein. Solid carriers or diluents included in such compositions or formulations may include, for example, ground natural minerals such as kaolins, alumina, calcium carbonate, silica, kieselguhr, clay, etc.; ground synthetic minerals such as various silicates and aluminosilicates and ground vegetable products such as bark, cornmeal, sawdust, cellulose powder and the like.

To manufacture solid compositions, the active substances are mixed with solid carriers or diluents such as those mentioned above and the mixture is ground to the appropriate size. Granules can be manufactured by dissolving an active compound in an organic solvent and applying the mixture, for example, by atomization, onto an absorptive granulated inert material, such as silica. Adhesives may be utilized to assist in the incorporation of the compound onto the solid particles. Pellets or granules can be manufactured by extrusion with appropriate carriers and binders.

Wettable powders, flowables, and pastes are obtained by mixing and grinding an active compound with one or more dispersing agents and/or solid carriers or diluents. Also included may be wetting agents and/or dispersing agents, for example, lignins, methyl cellulose, naphthalenesulfonic acid derivatives, fatty alcohol sulfates and various types of alkali and alkaline earth metal salts of fatty acids.

Emulsifiable concentrates are generally obtained by dissolving the active compound in an organic solvent, for example, butanol, cyclohexanone, xylenes, or higher boiling aromatic hydrocarbons. To obtain suspensions or emulsions in water, wetting agents are generally also added.

The compositions may also be used in the form of microcapsules. Microcapsules consist of fully enclosed or encapsulated droplets or granules containing the active compound, enclosed within an inert porous membrane, so as to permit escape of the encapsulated material into the surrounding medium or environment at a controlled rate.

Useful encapsulating materials include natural and synthetic rubbers or latexes, cellulosic materials, styrene-butadiene copolymers, polyacrylonitriles, polyacrylates, polyesters, polyamides, polyurethanes and starch xanthates.

It is possible to use highly concentrated liquid compositions containing up to about 95% by weight of the active compound, or even the active compound alone for those compounds which are liquids, when applying the compound in the form of a finely divided liquid by use of various atomizing equipment, for example by airplane crop-spraying techniques. For other purposes, however, the various types of compositions which can be utilized for these compounds will contain varying amounts of the compound according to the type of composition and the intended use.

In general, compositions may contain from 0.1 to 95% of the active compound, more preferably from 0.5 to 90%. Some typical compositions will contain an active compound as follows: Wettable powders, flowables and pastes--20 to 90% active compound; oil suspensions, emulsions, solutions and emulsifiable concentrates--5 to 90% active compound; aqueous suspensions--10 to 50% active compound; dusts and powders--1 to 25% active compound; granules and pellets--1 to 20% active compound.

The rate of application of the active compound to a locus to be controlled will depend on the activity of the compound and/or composition and the nature of the seeds and plants to be controlled and will vary from about 0.05 to about 50 pounds per acre (about 0.06 to about 56 kg/ha).

Compositions containing one or more of the active compounds described, in a herbicidally effective amount, may be applied to the plant or locus to be controlled in any conventional manner. Thus, powders and various liquid compositions containing the active compound can be applied by the use of power dusters, boom and hand sprayers and spray spray dusters, or applied from airplanes as mists or sprays. When applied in the latter method, they may be effective in very low dosages. To modify or control growth of germinating seeds or emerging seedlings, liquid compositions may be applied to the soil with conventional methods and may be distributed in the soil to a depth of one-half inch below the soil surface. The compositions need not be admixed with the soil particles, but can be applied merely by sprinkling on the surface of the soil.

Compositions including active compounds may also be applied by addition to irrigation waters supplied to the field to be treated. This method of application permits penetration of the compounds into the soil as the water is absorbed therein.

    ______________________________________                                         EXAMPLES OF TYPICAL COMPOSITIONS                                               ______________________________________                                         Ingredient          Weight %                                                   ______________________________________                                         Oil                                                                            Active Compound      1                                                         Oil solvent-heavy aromatic naphtha                                                                 99                                                         Total               100                                                        Emulsifiable Concentrate                                                       Active Compound     50                                                         Kerosene            45                                                         Emulsifying agent (mixture of long                                                                  5                                                         chain ethoxylated polyethers with                                              long chain sulfonate)                                                          Total               100                                                        Emulsifiable Concentrate                                                       Active Compound     90                                                         Kerosene             5                                                         Emulsifying agent (mixture of long                                                                  5                                                         chain ethoxylated polyethers with                                              long chain sulfonate)                                                          Total               100                                                        ______________________________________                                         Ingredient        Wt. %    Wt. %    Wt. %                                      ______________________________________                                         Dusts and/or Powders                                                           Active Compound   0.5      50.0     90.0                                       Attapulgite Clay Powder                                                                          93.5     44.0     4.0                                        Sodium lignin sulfonate                                                                          5.0      5.0      5.0                                        Sodium dioctyl sulfosuccinate                                                                    1.0      1.0      1.0                                        TOTAL             100.0    100.0    100.0                                      ______________________________________                                    

The compositions of the invention may comprise, in addition to one or more compounds of the invention, one or more compounds not of the invention but which possess biological activity. Compounds not of this invention may be other pesticidal agents, such as herbicides, fungicides, insecticides, acaricides, nematocides, bactericides, and plant growth regulators. Such compositions may also contain soil disinfectants or fumigants and may further contain fertilizers, thus making it possible to provide multi-purpose compositions containing one or more of the compounds described herein as well as, optionally, other pesticides and also fertilizers, all intended and formulated for use at the same locus. Accordingly, in yet a still further embodiment, the invention provides an herbicidal composition comprising a mixture of at least one herbicidal compound of formula (I) as hereinbefore defined with at least one other herbicide.

The other herbicide may be any herbicide not having the formula (I). It will generally be an herbicide having a complementary action in the particular application.

Examples of useful complementary herbicides include:

A. Benzo-2,1,3-thiodiazin-4-one-2,2-dioxides such as 3-isopropylbenzo-2,1,3-thiadiazin-4-one-2,2-dioxide (bentazone);

B. hormone herbicides, particularly the phenoxy alkanoic acids such as 4-chloro-2-methylphenoxyacetic acid (MCPA), S-ethyl 4-chloro-0-tolyloxy thioacetate (MCPA-thioethyl), 2-(2,4-dichlorophenoxy) propionic acid (dichlorprop), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), 4-(4-chloro-2-methylphenoxy)butyric acid (MCPB), 2,4-dichlorophenoxyacetic acid (2,4-D), 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB), 2-(4-chloro-2-methylphenoxy) propionic acid (mecoprop), 3,5,6-trichloro-2-pyridyloxyacetic acid (trichlopyr), 4-amino-3,5-dichloro-6-fluoro-2-pyridyloxyacetic acid (fluroxypyr), 3,6-dichloropyridine-2-carboxylic acid (clopyralid), and their derivatives (e.g. salts, esters and amides);

C. 1,3-dimethylpyrazole derivatives such as 2-[4-dichlorobenzoyl) 1,3-diemthylpyrazol-5-yloxy] acetophenone (pyrazoxyfen), 4-(2,4-dichlorobenzoyl)1,3-dimethylpyrazol-5-yltoluene sulfonate (pyrazolate) and 2-[4-(2,4-dichloro-m-toluolyl)-1,3-dimethylpyrazol-5-yloxy]-4'-methylacetophenone (benzofenap);

D. Dinitrophenols and their derivatives (e.g. acetates such as 2-methyl-4,6-dinitrophenol (DNOC), 2-t-butyl-4,6-dinitrophenol (dinoterb), 2-sec.-butyl-4,6-dinitrophenol (dinoseb) and its ester, dinoseb acetate;

E. dinitroaniline herbicides such as N',N'-diethyl-2,6-dinitro-4-trifluoromethyl-m-phenylenediamine (dinitramine), 2,6-dinitro-N,N-dipropyl-4-trifluoromethylaniline (trifluralin), N-ethyl-N-(2-methylallyl)-2,6-dinitro-4-trifluoromethylaniline (ethalfluralin), N-(1-ethylpropyl)-2,6-dinitro-3,4-xylidine (pendimethalin); and 3,5-dinitro-N⁴, N⁴ -dipropylsulphanilamide (oryzalin);

F. arylurea herbicides such as N'-(3,4-dichlorophenyl)-N,N-dimethylurea (diuron), N,N-dimethyl-N'-[3-(trifluoromethyl) phenyl]urea (flumeturon), 3-(3-chloro-4-methoxyphenyl)-1,1-dimethylurea (metoxuron), 1-butyl-3-(3,4-dichlorophenyl)-1-methylurea (neburon), 3-(4-isopropylphenyl)-1,1-dimethylurea (isoproturon), 3-(3-chloro-p-tolyl)-1,1-dimethylurea (chlorotoluron), 3-[4-(4-chlorophenoxy) phenyl]-1,1-dimethylurea (chloroxuron), 3-(3,4-dichlorophenyl)-1-methylurea (linuron), 3-(4-chlorophenyl)-1-methoxy-1-methylurea (monolinuron), 3-(4-bromo-4-chlorophenyl)-1-methoxy-1-methylurea (chlorobromuron), 1-(1-methyl-1-phenylethyl)-3-p-tolylurea (daimuron), and 1-benzothiazol-2-yl-1,3-dimethylurea (methabenzthiazuron);

G. phenylcarbamoyloxyphenylcarbamates such as 3-[methoxycarbonylamino]phenyl (3-methylphenyl)carbamate (phenmedipham) and 3-[ethoxycarbonylamino]-phenyl phenylcarbamate (desmedipham);

H. 2-phenylpyridazin-3-ones such as 5-amino-4-chloro-2-phenylpyridazin-3-one (chloridazon), and 4-chloro-5-methylamino-2-(α, α, α-trifluoro-m-tolyl) pyridazin-3(2H)-one (norflurazon);

I. uracil herbicides such as 3-cyclohexyl-5,6-trimethyleneuracil (lenacil), 5-bromo-3-sec.-butyl-6-methyluracil (bromacil) and 3-t-butyl-5-chloro-6-methyl-uracil (terbacil);

J. triazine herbicides such as 2-chloro-4-ethylamino-6-(i-propylamino)-1,3,5-triazine (atrazine), 2-chloro-4,6-di(ethylamino)-1,3,5-triazine (simazine), 2-azido-4-(i-propylamino)-6-methylthio-1,3,5-triazine (aziprotryne), 2-(4-chloro-6-ethylamino-1,3,5-triazin-2-ylamino)-2- methylpropionitrile (cyanazine), N², N⁴ -di-isopropyl-6-methylthio-1,3,5-triazine-2,4-diamine (prometryn), N² -(1,2-dimethylpropyl)-N⁴ -ethyl-6-methylthio-1,3,5-triazine-2,4-diamine (dimethametryn), N²,N⁴ -diethyl-6-methylthio-1,3,5-triazine-2,4-diamine (simetryne), and N² -tert.-butyl-N⁴ -ethyl-6-methylthio-1,3,5-triazine-2,4-diamine (terbutryn);

K. phosphorothioate herbicides such as S-2-methylpiperidinocarbonyl-methyl O,O-dipropyl phosphorodithioate (piperophos), S-2-benzenesulphonamidoethyl O,O-diisopropyl phosphonodithioate (bensulide), and O-ethyl O-6-nitro-m-tolyl sec.-butylphosphoramidothioate (butamifos);

L. thiolcarbamate herbicides such as S-ethyl N-cyclohexyl-N-ethyl thiocarbamate (cycloate), S-propyl dipropyl-thiocarbamate (vernolate), S-ethyl-azepine-1-carbothioate (molinate), S-4-chlorobenzyl diethylthiocarbamate (thiobencarb), S-ethyl di-isobutyl-thiocarbamate (butylate)*, S-ethyl di-isopropylthiocarbamate (EPTC)*, S-2,3,3-trichloroallyl diisopropyl thiocarbamate (triallate), S-2,3-dichloroallyl diisopropyl thiocarbamate (diallate), S-benzyl 1,2-dimethylpropyl (ethyl) thiocarbamate (esprocarb), S-benzyl di(sec.-butyl) thiocarbamate (tiocarbazil), 6-chloro-3-phenylpyridazin-4-yl S-octyl thiocarbamate (pyridate), and S-1-methyl-1-phenylethylpiperidine-1-carbothioate (dimepiperate);

M. 1,2,4-triazin-5-one herbicides such as 4-amino-4,5-dihydro-3-methyl-6-phenyl-1,2,4-triazine-5-one (metamitron) and 4-amino-6-butyl-4,5-dihydro-3-methylthio-1,3,4-triazin-5-one (metribuzin);

N. benzoic acid herbicides such as 2,3,6-trichlorobenzoic acid (2,3,6-TBA), 3,6-dichloro-2-methoxybenzoic acid (dicamba) and 3-amino-2,5-dichlorobenzoic acid (chloramben);

O. anilide herbicides such as 2-chloro-2',6'-diethyl-N-(2-propoxyethyl)acetanilide (pretilachlor), N-butoxymethyl-2-chloro-2',6'-diethylacetanilide (butachlor), the corresponding N-methoxy compound (alachlor), the corresonding N-i-propyl compound (propachlor), 3',4'- dichloropropionanilide (propanil), 2-chloro-N-[pyrazol-1-ylmethyl]acet-2'-6'xylidide(metazachlor), 2-chloro-6'-ethyl-N-(2-methoxy-1-methylethyl) acetotoluidide (metolachlor), 2-chloro-N-ethoxymethyl-6'-ethylacetotoluidide (acetochlor), and 2-chloro-N-(2-methoxyethyl)acet-2',6'-xylidide (dimethachlor);

P. dihalobenzonitrile herbicides such as 2,6-dichlorobenzonitrile (dichlobenil), 3,5-dibromo-4-hydroxy-benzonitrile (bromoxynil) and 3,5-diiodo-4-hydroxy-benzonitrile (ioxynil);

Q. haloalkanoic herbicides such as 2,2-dichloropropionic acid (dalapon), trichloroacetic acid (TCA) and salts thereof;

R. diphenylether herbicides such as ethyl 2-[5-2-chloro-trifluoro-p-tolyloxy)-2-nitrobenzoyl]oxy propionate (lactofen), D-[5-(2-chloro-α,α,α-trifuoro-p-tolyl)-2-nitrobenzoyl] gycolic acid (fluroglycofen) or salts or esters thereof, 2,4-dichlorophenyl-4-nitrophenyl ether (nitrofen), methyl-(2,4-dichlorophenoxy)-2-nitrobenzoate (bifenox), 2-nitro-5-(2-chloro-4-trifluoromethyl-phenoxy) benzoic acid (acifluorfen) and salts and esters thereof, 2-chloro-4-trifluoromethylphenyl 3-ethoxy-4-nitrophenyl ether (oxyfluorfen) and 5-[2-chloro-4-(trifluoromethyl)phenoxy]-N-(methylsulfonyl)-2-nitrobenzamide (fomesafen); 2,4,6-trichlorophenyl 4-nitrophenyl ether (chlornitrofen) and 5-(2,4-dichlorophenoxy)-2-nitroanisole (chlomethoxyfen);

S. phenoxyphenoxypropionate herbicides such as (RS)-2-[4-(2,4-dichlorophenoxy) phenoxy] propionic acid (diclofop) and esters thereof such as the methyl ester, 2-[4-(5-trifluoromethyl)-2-(pyridinyl)oxy] phenoxypropanoic acid (fluazifop) and esters thereof, 2-[4-(3-chloro-5-trifluoromethyl)-2-pyridinyl)oxy] phenoxypropanoic acid (haloxyfop) and esters thereof, 2-[4-(6-chloro-2-quinoxalinyl)oxy] phenoxypropanoic acid (quizalofop) and esters thereof and (±)-2-[4-(6-chlorobenxoxazol-2-yloxy)phenoxy] propionic acid (fenoxaprop) and esters thereof such as the ethyl ester;

T. cyclohexanedione herbicides such as 2,2-dimethyl-4,6-dioxo-5-[1-(2-propenyloxyimino)butyl] cyclohexane carboxylic acid (alloxydim) and salts thereof, 2-(1-ethoxyimino) butyl-5-[2-(ethylthio)-propyl]-3-hydroxy-2-cyclohexan-1-one (sethoxydim), 2-(1-ethoxyimino)butyl-3-hydroxy-5-thian-3-ylcyclohex-2-enone (cycloxydim), 2-[1(ethoxyimino)propyl]-3-hydroxy-5-mesitylcyclohex-2-enone (tralkoxydim), and (±)-2-(E)-1-[(E)-3-chloroallyloximino] propyl-5-[2-(ethylthio)propyl]-3-hydroxycyclohex-2-enone (clethodim);

U. sulfonyl urea herbicides such as 2-chloro-N (4-methoxy-6-methyl-1,3,5-triazin-2-yl)-aminocarbonyl) benzenesulphonamide (chlorosulfuron), methyl 2-[([(4,6-dimethyl-2-pyrimidinyl)amino]-carbonyl)amino]-sulphonylbenzoic acid (sulfometuron), 2-([(3-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)carbonyl]amino)-sulphonyl)benzoic acid (metsulfuron) and esters thereof; -(4,6-dimethoxypyrimidin-2-ylcarbamoylsuphamoyl)-O-toluic acid (benzsulfuron) and esters thereof such as the ester thereof methyl, 3-[3-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)ureido- sulphonyl]thiophene-2-carboxylate (DPX-M6313), 2-(4-chloro-6-methoxy pyrimidin-2-yl carbamoylsulphamoyl benzoic acid (chlorimuron) and esters such as the ethyl ester thereof, 2-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulphamoyl)-N,N-dimethyl-nicotinamide, 2-[4,6-bis(difluoromethoxy)pyrimidin-2-ylcarbamoylsulphamoyl] benzoic acid (pirimisulfuron) and esters such as the methyl ester thereof, 2-[3-(4-methoxy-6-methyl-1,3,5-triazin-zyl)-3-methylureidosulphonyl] benzoic acid esters such as the methyl ester thereof (DPX-LS300) and 5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulphamoyl)-1-methylpyrazole-4-carboxylic acid (pyrazosulfuron);

V. imidazolidinone herbicides such as 2-(4,5-dihydro-4-isopropyl-4-methyl-5-oxoimidazol-2-yl) quinoline-3-carboxylic acid (imazaquin), methyl 6-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-m-toluate and p-toluate isomer (imazamethabenz), 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl) nicotinic acid (imazapyr) and isopropylammonium salts thereof, (RS)-5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl) nicotinic acid (imazethapyr);

W. arylanilide herbicides such as benzoyl-N-3-chloro-4-fluorophenyl)-L-alanine (flamprop) and esters thereof, ethyl N-benzoyl-N-(3,4-dichlorophenyl)-DL-alaninate (benzoylprop-ethyl), N-(2,4-difluorophenyl)-2-(3-trifluoromethyl)phenoxy-3-pyridinecarboxamide (diflufenican);

X. amino acid herbicides such as N-(phosphonomethyl)-glycine (glyphosate) and DL-homoalanin-4-yl (methyl)-phosphinic acid (gluyfosinate) and their salts and esters, trimethylsulfonium N-(phosphonomethyl)-glycine (sulphosate), and bilanafos;

Y. organoarsenical herbicides such as monosodium methanearsonate (MSMA);

Z. herbicidal amide derivative such as (RS)-N,N-diethyl-2-(1-naphthyloxypropionamide) (napropamide), 3,5-dichloro-N-(1,1-dimethylpropynyl)benzamide (propyzamide), (R)-1-(ethylcarbamoyl)ethyl carbanilate (carbetamide), N-benzyl-N-isopropylpivalamide (tebutam), (RS)-2-bromo-N-(α,α-dimethyl-benzyl)-3,3-dimethylbutyramide (bromobutide), N-[3-(1-ethyl-1-methylpropyl)-isoxazol-5-yl]2,6-dimethoxybenzamide, (isoxaben), N-phenyl-2-(2-naphthyloxy) propionamide (naproanilide), N,N-dimethyl-diphenylacetamide (diphenamid), and N-(1-naphthyl)-phthalamic acid (naptalam);

AA. miscellaneous herbicides including 2-ethoxy-2,3-dihydro-3,3-dimethylbenzofuran methanesulfonate (ethofumesate), 7-oxabicyclo (2.2.1)heptane,1-methyl-4-(1-methylethyl)-2-(2-methylphenylmethoxy)-exo (cinmethylin), 1,2-dimethyl-3,5-diphenylpyrazolium ion (difenzoquat) and salts thereof such as the methyl sulfate salt, 2-(2-chlorobenzyl)-4,4-dimethyl-1,2-oxazoldin-3-one (clomazone), 5-tert.-butyl-3-(2,4-dichloro-5-isopropoxyphenyl)-1,3,4-oxadiazol-2(3H)-one (oxadiazon), 3,5-dibromo-4-hydroxy benzaldehyde 2,4-dinitrophenyloxime (bromofenoxim), 4-chlorobut-2-ynyl-3-chlorocarbanilate (barban), (RS)-2-(3,5-dichlorophenyl)-2-(2,2,2-trichloroethyl)oxirane (tridiphane), (3RS,4RS;3RS,4SR)-3-chloro-4-chloromethyl-1-α,α,-α-trifluoro-m-tolyl-2-pyrrolidone (in the ratio 3:1) (flurochloridone), dichloroquinoline 8-carboxylic acid (quinchlorac) and 2-(1,3-benzothiazol-2-yl-oxy)-N-methylacetanilide (mefanacet);

BB. examples of useful contact herbicides include bipyridylium herbicides such as those in which the active entity is the 1,1'-dimethyl-4,4'-dipyridylium ion (paraquat) and those in which the active entity is the 1,1'-ethylene-2,2'-dipyridylium ion (diquat).

* These compounds are preferably employed in combination with a safener such as 2,2-dichloro-N,N-di-2-propenylacetamide (dichlormid). 

What is claimed is:
 1. A compound having the formula ##STR6## in which R₁ is C₃ -C₆ alkyl or C₅ -C₆ cycloalkyl;R₂ is C₁ -C₄ alkyl; R₃ is phenyl, optionally substituted by methoxy, one or two methoxy groups, one methyl and one methoxy group, or one or two halogens; and R₄ and R₅ are independently C₃ -C₄ alkyl.
 2. A compound according to claim 1 in which R₄ and R₅ are identical alkyl groups.
 3. A compound according to claim 1 in which R₄ and R₅ are different alkyl groups.
 4. A compound according to claim 1 in which R₁ and R₂ are both alkyl.
 5. A compound according to claim 1 in which R₂ is methyl.
 6. A compound according to claim 1 in which R₂ is ethyl.
 7. A compound according to claim 1 in which R₂ is isopropyl.
 8. A compound according to claim 1 in which R₂ is n-butyl.
 9. A compound according to claim 1 in which R₁ is n-propyl, R₂ is methyl, R₃ is phenyl and R₄ and R₅ are both n-propyl.
 10. A compound according to claim 1 in which R₁ is n-propyl, R₂ is ethyl, R₃ is phenyl, and R₄ and R₅ are both n-propyl.
 11. A compound according to claim 1 in which R₁ is n-propyl, R₂ is n-butyl, R₃ is phenyl, and R₄ and R₅ are both n-propyl.
 12. A compound according to claim 1 in which R₁ is n-butyl, R₂ is methyl, R₃ is 4-chlorophenyl and R₄ and R₅ are both n-propyl.
 13. A compound according to claim 1 in which R₁ is n-propyl, R₂ is isopropyl, R₃ is phenyl, and R₄ and R₅ are both n-propyl.
 14. A compound according to claim 1 in which R₁ is n-propyl, R₂ is methyl, R₃ is 4-ethylphenyl, and R₄ and R₅ are both n-propyl.
 15. A compound according to claim 1 in which R₁ is n-propyl, R₂ is methyl, R₃ is 2-methylphenyl and R₄ and R₅ are both n-propyl.
 16. A compound according to claim 1 in which R₁ is n-propyl, R₂ is methyl, R₃ is 3-trifluoromethylphenyl and R₄ and R₅ are both n-propyl.
 17. A compound according to claim 1 in which R₁ is n-propyl, R₂ is methyl, R₃ is 2-methyl, 4-methoxyphenyl and R₄ and R₅ are both n-propyl.
 18. A compound according to claim 1 in which R₁ is n-propyl, R₂ is methyl, R₃ is 3-methylphenyl and R₄ and R₅ are both n-propyl.
 19. A compound according to claim 1 in which R₁ is n-propyl, R₂ is methyl, R₃ is phenyl and R₄ and R₅ are both n-butyl.
 20. A method of controlling undesirable vegetation by applying to said vegetation or the locus thereof an herbicidally effective amount of a compound having the formula ##STR7## in which R₁ is C₃ -C₆ alkyl or C₅ -C₆ cycloalkyl;R₂ is C₁ -C₄ alkyl; R₃ is phenyl, optionally substituted by methoxy, one or two methoxy groups, one methyl and one methoxy group, or one or two halogens; and R₄ and R₅ are independently C₃ -C₄ alkyl.
 21. A method according to claim 20 in which the compound is applied subsequent to the emergence of the vegetation.
 22. A method according to claim 20 in which R₄ and R₅ are identical alkyl groups.
 23. A method according to claim 20 in which R₄ and R₅ are different alkyl groups.
 24. A method according to claim 20 in which R₁ and R₂ are both alkyl.
 25. A method according to claim 20 in which R₂ is methyl.
 26. A method according to claim 20 in which R₂ is ethyl.
 27. A method according to clam 20 in which R₂ is isopropyl.
 28. A method according to claim 20 in which R₂ is n-butyl.
 29. A method according to claim 20 in which R₁ is n-propyl, R₂ is methyl and R₃ is phenyl and R₄ and R₅ are both n-propyl.
 30. A method according to claim 20 in which R₁ is n-propyl, R₂ is ethyl, R₃ is phenyl, and R₄ and R₅ are both n-propyl.
 31. A method according to claim 20 in which R₁ is n-propyl, R₂ is n-butyl, R₃ is phenyl, and R₄ and R₅ are both n-propyl.
 32. A method according to claim 20 in which R₁ is n-butyl, R₂ is methyl, R₃ is 4-chlorophenyl and R₄ and R₅ are both n-propyl.
 33. A method according to claim 20 in which R₁ is n-propyl, R₂ is isopropyl, R₃ is phenyl, and R₄ and R₅ are both n-propyl.
 34. A method according to clam 20 in which R₁ is n-propyl, R₂ is methyl, R₃ is 4-ethylphenyl, and R₄ and R₅ are both n-propyl.
 35. A method according to claim 20 in which R₁ is n-propyl, R₂ is methyl, R₃ is 2-methylphenyl and R₄ and R₅ are both n-propyl.
 36. A method according to claim 20 in which R₁ is n-propyl, R₂ is methyl, R₃ is 3-trifluoromethylphenyl and R₄ and R₅ are both n-propyl.
 37. A method according to claim 20 in which R₁ is n-propyl, R₂ is methyl, R₃ is 2-methyl,4-methoxyphenyl and R₄ and R₅ are both n-propyl.
 38. A method according to claim 20 in which R₁ is n-propyl, R₂ is methyl, R₃ is 3-methylphenyl and R₄ and R₅ are both n-propyl.
 39. A method according to claim 20 in which R₁ is n-propyl, R₂ is methyl, R₃ is phenyl and R₄ and R₅ are both n-butyl.
 40. An herbicidal composition comprising(a) an herbicidally effective amount of a compound according to claim 1; and (b) an inert diluent or carrier suitable for use with herbicides. 